With the development of service demands of users and network technologies, hybrid networking has become a trend, that is, at least two networks simultaneously provide coverage and simultaneously provide services to users. For example, hybrid coverage of a Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) network and a Time Division-Long Term Evolution (TD-LTE) network, that is, a hybrid networking scenario of TD-SCDMA and TD-LTE, is already implemented at present, and because this scenario easily satisfies a demand of a user, this scenario is widely applied. Because both networks in the foregoing hybrid networks, for example, the TD-SCDMA network and the TD-LTE network, use a Time Division Duplex (TDD) system to perform data communication and an uplink frequency and a downlink frequency are the same in the TDD system, in a communication process, downlink channel information may be estimated by using uplink channel information; a premise of this estimation is that a channel correction of a remote radio unit (RRU) needs to be completed. In the TD-SCDMA network and the TD-LTE network, a correction signal is sent in a guard period (GP) to complete the channel correction of the RRU.
In an actual application, because carrier frequencies used in networks in hybrid networks are similar or the same, for example, the TD-SCDMA network and the TD-LTE network, in the hybrid networking scenario of TD-SCDMA and TD-LTE, a signal of the TD-SCDMA network may leak to a GP of the TD-LTE network, thereby causing interference to a correction signal in the GP; and a signal of the TD-LTE network may also leak to a GP of the TD-SCDMA network, which also causes interference to a correction signal in the GP. As can be seen, interference to a correction signal exists in hybrid networks at present.